The invention relates to a process for producing a foldable blank made of plastic foam for forming packs, insulations etc. The invention further relates to an insulating material formed from such a blank.
The production of such foldable blanks from plastic foam presents problems in many respects. On the one hand, there is the danger that, when the blank is folded, cracks will occur at the folding edges. On the other hand, folding or bending lines are very complicated to form in plastic foam.
To prevent an undesirable breaking of the folding or bending lines of the blank, it is already known to provide a web of material made of plastic foam or a blank already severed from this with appropriate embossings. These embossings have hitherto been made by reheating the web of material cooled after foaming, until it can experience permanent deformation, that is to say the necessary folding and bending lines can be pressed permanently into the plastic foam material. Apart from the fact that the subsequent reheating of the web of material involves an additional outlay incurring considerable energy costs, a secondary expansion of the reheated plastic foam occurs and leads to undesirable losses of strength.